JPH0733244Y2 - Corona discharger - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a corona discharger used in an image forming apparatus such as a copying machine.

[Conventional technology]

For example, in an electrophotographic copying machine, a main charging corona discharger for charging the photosensitive drum, a transfer corona discharger for transferring the toner image on the photosensitive drum onto the paper, and the paper from the photosensitive drum are used. Various types of corona dischargers such as a corona discharger for separating sheets for separation are used.

This corona discharger is generally a shield case having a U-shaped cross section having a discharge opening, and a corona discharge wire stretched over the longitudinal direction of the shield case (hereinafter,
Charge wire). Further, in a structure in which the charge wire is not directly fixed to the shield case but can be separated from each other, a shield frame body having insulating blocks fixed at both ends is fitted into the shield case, and the space between the insulating blocks is increased. The charge wire is stretched. The shield frame body, the insulating block and the charge wire can be integrally pulled out from the shield case.

By the way, in a corona discharger of a copying machine, when it is used for a long period of time, dust such as toner and paper dust adheres to or accumulates on the charge wire and the inner surface of the shield case. When such dust adheres, in a discharge state, the charged state of the photosensitive drum varies in the longitudinal direction of the shield case, and if the adhered matter is conductive, a leak occurs in an extreme case.
Further, in the corona discharger for separating the paper, there is a problem that the paper cannot be separated.

Therefore, maintenance is required every predetermined period,
In the conventional corona discharger, when the dirt on the shield case is removed, the charge wire is pulled out from the shield case together with the shield frame body and the dirt on the inner surface of the shield case is wiped off with a waste cloth or the like as described above.

Further, in the case where the charge wire is fixedly stretched in the shield case, as shown in JP-A-51-133029, a cleaning member for cleaning the charge wire and the inner surface of the shield case is provided in the shield case. It has been proposed that the cleaning member be provided along with the charge wire to slide along the charge wire through the sliding plate in the shield case to remove the above-mentioned dirt.

[Problems to be solved by the device]

As described above, even in the case where the charge wire can be pulled out, the work of wiping off the toner adhering to the inner surface of the shield case and the work of collecting dust such as paper dust are troublesome. In particular, in the corona discharger for transfer and the corona discharger for paper separation, a claw for preventing paper from entering the shield case, nylon wire, etc. are provided on the upper surface of the shield case. It is very difficult to wipe off with a waste cloth.

Further, even if the cleaning member as shown in the above publication is used,
Eventually, dust remains inside the shield case, making it impossible to perform sufficient cleaning.

An object of the present invention is to provide a corona discharger capable of easily and reliably cleaning the inside of the shield case.

[Means for Solving the Problems]

A corona discharger according to the present invention includes a shield case having an opening for discharge, a shield frame body slidably inserted in the shield case, and a pair of shield frame bodies fixed to both ends of the shield frame body. The insulating frame, the corona discharge wire stretched between the pair of insulating blocks, and the side wall of one insulating block of the pair of insulating blocks are provided outside the side wall, and the shield frame body is fitted in the shield case. And a cleaning member that is disposed apart from the shield case side end in the inserted state and that can slide the insulating block into contact with the inner surface of the shield case and clean the inner surface when the insulating block slides in the shield case together with the shield frame. ing.

[Action]

In the present invention, when the shield frame is pulled out from the shield case for maintenance or the like, the insulating block fixed to the shield frame slides in the shield case. At this time, since the cleaning member is provided on the outer side of the side wall of the insulating block, the cleaning member is brought into sliding contact with the inner surface of the shield case, thereby removing toner such as toner and paper dust attached to the inner surface of the case. Therefore, it is not necessary to manually wipe the inner surface of the shield case with a waste cloth, and the inner surface of the shield case can be easily and reliably cleaned.

Further, the cleaning member is arranged apart from the shield case side end in a state where the shield frame body is fitted and inserted in the shield case. Therefore, as compared with the case where the cleaning member constantly contacts the inner surface of the shield case, the fatigue of the cleaning member can be reduced. As a result, the dust on the inner surface of the shield case can be reliably removed. Further, by disposing the cleaning member away from the shield case, even if conductive dust adheres to the cleaning member, a creeping discharge is generated between the charge wire and the shield case via the cleaning member and the insulating block. Unlikely to occur.

〔Example〕

FIG. 4 shows a sectional structure of a copying machine using a corona discharger according to an embodiment of the present invention. In FIG. 4, an original table 12 is provided on the upper surface of the copying machine 11, and an original conveying means 13 is provided on the original table 12. The original is placed on the upper right side of the copying machine main body 11 in the figure, and is conveyed leftward in the figure by the conveying rollers provided in the original table 12 and the original conveying means 13.

Inside the copying machine main body 11, an exposure device 14 for reading a document is provided above the main body. The exposure device 14 is composed of a light source, a Selfoc lens, and the like. A photoconductor drum 15 on which an electrostatic latent image is formed is arranged in the center of the copying machine main body 11. Around the photosensitive drum 15, a main charging corona discharger 16 for charging the photosensitive drum 15 to a predetermined electric charge, a developing device 17 for developing an electrostatic latent image,
Transfer corona discharger for transferring toner images to paper 1
8. A corona discharger 19 for separating a sheet from the photoconductor drum 15 and a cleaning device 20 for removing the residual toner on the photoconductor drum 15 are arranged.

Further, a paper feed cassette 8 is detachably attached to the lower part of the copying machine main body 11, and between the paper feed cassette 8 and an image forming portion constituted by the photosensitive drum 15 and the like,
A paper feed path 21 is provided. A paper discharge path 22 is provided on the downstream side of the image forming unit. A fixing device 30 that fixes the toner image on the conveyed sheet is disposed further downstream of the sheet discharge path 22.

Next, details of the corona discharger will be described with reference to FIGS. In this embodiment, the transfer corona discharger 18 and the paper separating corona discharger 19 are unitized and integrally configured. FIG. 1 is an exploded view of the unitized corona dischargers 18 and 19 (hereinafter, these unitized corona dischargers are simply referred to as corona dischargers). As shown in the figure, both corona dischargers 18, 19 are
The partition walls 9 are symmetrically arranged.

The corona discharger includes a metallic shield case 25, a shield frame body 26 slidably fitted in the shield case 25, and a pair of insulating blocks 27, 28 formed of resin in a box shape. , And a charge wire 29 stretched between the insulating blocks 27 and 28. The insulating block
27 and 28 are fixed to the upper surfaces of both ends of the shield frame body 26 with screws or the like.
And charge wire 29 as one, shield case 25
Can be pulled out or inserted as shown in FIG.

The shield case 25 has a discharge opening at the top and is formed in a U-shaped cross section, and can be attached to the frame side plate of the copying machine main body 11. And the upper end of the side wall is
Each of them is bent in the paper transport direction. A protrusion 25c is formed by cutting and raising a part of the one bent portion 25a, and a notch 25d is formed in the other bent portion 25b. And this protrusion 25c
As shown in FIG. 2, the notch 25d is used to hang a nylon wire 45 for preventing the paper from entering the shield case 25.

The nylon wire 45 is stretched across the longitudinal center of the shield case 25 along the paper transport direction (from the top to the bottom in FIG. 2). As a result, even if the curled paper is conveyed, the end of the paper is spread outward along the nylon wire 45 and does not enter the shield case 25.

As shown in FIG. 1, a boss 30 is formed on the insulating block 27 in the vicinity of an outer wall (left side in the drawing).
A protrusion 31 is provided on the upper surface of the boss 30, and one end of a spring 32 is locked to the protrusion 31. The spring 32 is for setting the tension of the charge wire 29, and one end of the charge wire 29 is fixed to the other end. An insulating film 40 is provided above the spring 32 so as to cover the spring 32. This insulating film 40 is for increasing the creeping distance between the spring 32 and the shield case 25, so that even if a high voltage is applied to the charge wire 29, creeping discharge is less likely to occur. Has become. Also,
A lid 42 is detachably attached to the upper surface of the insulating block 27. An engaging portion 42a is formed on a side portion of the lid 42 so as to project downward, and the engaging portion 42a can be engaged with a claw 27f provided on a side wall of the insulating block 27.

Further, a cleaning member formed of an acrylic pile seal material is provided on the outer side of both side walls of the insulating block 27 in the sheet conveying direction.
34 is attached by double-sided tape or the like. The cleaning member 34 is provided so as to come into sliding contact with the inner surface of the shield case 25 when the shield frame 26 slides in the shield case 25. In addition, the shield case 25 and the shield frame 26
As shown in FIG. 2, when the cleaning member 34 is assembled in a normal state, the cleaning member 34 is arranged so that there is a gap h between the cleaning member 34 and the shield case 25 side end. ing.

As shown in FIG. 1, the insulating block 28 has a boss 35 at its substantially central portion. A female screw is formed on the boss 35, and a screw 37 and a washer 36 screwed into the boss 35.
Thus, the other end of the charge wire 29 is fixed. Similarly to the above, an insulating film 41 is provided above the screw 37 so as to cover the screw 37, and a lid 43 is detachably attached to the upper surface of the insulating block 28. The lid 43 has a locking portion 43a formed on the side thereof.
However, it can be locked to the claw 28f on the side wall of the insulating block 28. A voltage application terminal 46 is provided below the insulating block 28, and the terminal 46 is electrically connected to the screw 37 and the charge wire 29.

Next, the function and effect will be described.

The operation of the copying machine body is exactly the same as the conventional operation. The original is conveyed on the original table 12 by each roller such as the original conveying means 13 and the image information thereof is read by the exposure device 14. The image information of the document is recorded as an electrostatic latent image on the photosensitive drum 15 and is developed by the developing device 17. On the other hand, the paper is conveyed from the paper feed cassette 8 or the like via the paper feed path 21, and the toner image is transferred onto the paper by the transfer corona discharger 18. After that, the sheet on which the toner image is transferred is separated from the photoconductor drum 15 by the sheet separation corona discharger 19, and is discharged to a discharge tray (not shown) via the discharge path 22 and the fixing device 30. .

When such a copying machine is used for a long period of time, dust such as toner and paper powder adheres to and accumulates on the inner surface of the shield case 25. Therefore, after a predetermined period of operation, the shield frame 26 is pulled out from the shield case 25 from the state shown in FIG. 2 as shown in FIG. Then, the insulating block 27 slides in the shield case 25, and the cleaning member 34 provided on the outer side of the side wall thereof is brought into sliding contact with the inner surface of the shield case 25. As a result, dust such as toner attached to the inner surface of the shield case 25 is removed.

In this embodiment, the dust such as toner adhered to the inner surface of the shield case 25 can be removed only by pulling out the shield frame 26 from the shield case 25. Therefore, unlike the conventional device, it is not necessary to wipe the inner surface of the shield case 25 with a waste cloth or the like. In particular, as shown in FIG.
When the nylon wire 45 is stretched over the upper surface of the shield case 25, the dust removal operation becomes very easy.

Further, in this embodiment, as shown in FIG. 2, a gap h is formed between the cleaning member 34 and the shield case 25 side end in the assembled state.
Is provided. Therefore, even when conductive dust such as toner or carrier adheres to the cleaning member 34, the charge wire 29 is passed through the cleaning member 34 and the insulating block 27.
A creeping discharge is unlikely to occur between the equal shield cases 25. Also,
For the same reason, the fatigue of the cleaning member 34 can be reduced as compared with the case where the cleaning member 34 is always located on the inner surface of the shield case 25. As a result, the initial state of the cleaning member 34 can be maintained for a long time, and the dust on the inner surface of the shield case 25 can be reliably removed for a long period of time.

[Other Examples]

(A) In addition to the configuration of the above embodiment, a dust receiver may be provided on the side plate of the copying machine main body 11.

FIG. 5 shows an embodiment in this case. As shown in the figure, the shield case 25 is fixed to the side plates 46 and 47 of the copying machine body, and the dust receiver 48 is fixed to the side plate 46 on the pull-out side (left side in the drawing) of the shield frame 26. .

As shown in FIGS. 5 and 6, the dust receiver 48 is formed in a box shape, and the side wall 48a located inside the device is in contact with the shield frame 26, the insulating blocks 27, 28 and the cleaning member 34. A large hole 49 is formed so that the large hole 49 can pass therethrough. Further, the cleaning member 34 is provided on the side wall 48b located on the outer side of the opposite device.
A small hole 50 is formed so as to pass through while contacting.

In such an embodiment, when the shield frame 26 is pulled out, the dust on the inner surface of the shield case 25 is removed by the cleaning member 34, and the removed dust receives the dust receiver.
Fall within 48. When the shield frame 26 is further pulled out, the cleaning member 34 is pulled out while being in contact with the small hole 50 of the dust receiver 48, whereby the dust such as toner adhering to the cleaning member 34 is squeezed off and the dust is removed. Receiving 48
Fall inside.

In this way, the dust collected by the cleaning member 34 and the dust attached to the cleaning member 34 can be reliably stored in the dust receiver 48. As a result, the dust attached to the cleaning member 34 is removed, and the dust attached to the cleaning member 34 does not stain the inner surface of the shield case 25 again.

(B) In the above embodiment, the cleaning member 34 is attached to the end of the insulating block 27 from the inside of the apparatus. However, the mounting position of the cleaning member 34 is outside the side wall of the insulating block 27, At any time, if it is a position that slides on the inner surface of the shield case 25,
There is no particular limitation.

(C) In the above embodiment, the cleaning member 34 is provided only on the side wall of the insulating block 27, but it is also provided on the bottom surface of the insulating block 27.
The top surface of the bottom wall of the shield case 25 may be cleaned by this cleaning member.

(D) In the above embodiment, the cleaning member 34 is composed of an acrylic pile seal member, but it may be composed of a rubber-based material such as felt, carbon brush, urethane rubber, or cloth.

(E) In the above embodiment, the corona discharger of the present invention is applied to the transfer corona discharger and the paper separating corona discharger, but the same can be applied to other corona dischargers for main charging. The same effect as the embodiment is obtained.

(F) In the above embodiment, the present invention is applied to the copying machine,
Of course, it can be similarly applied to other image forming apparatuses.

[Effect of device]

As described above, according to the present invention, when the shield frame body to which the insulating block is fixed is pulled out from the shield case, the inner surface of the shield case can be cleaned by the cleaning member provided outside the side wall of the insulating block. The work of wiping the inside with a waste cloth is not required, and the inside of the shield case can be easily and reliably cleaned. When the cleaning member is arranged apart from the end on the side of the shield case in a state where the shield frame body is fitted and inserted in the shield case, the settling of the cleaning member can be reduced. As a result, the dust on the inner surface of the shield case can be reliably removed. Furthermore, since the cleaning member is arranged away from the end on the shield case side, even if conductive dust adheres to the cleaning member, the creeping surface between the charge wire and the shield case is increased through the cleaning member and the insulating block. Discharge is hard to occur.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a corona discharger according to an embodiment of the present invention, FIG. 2 is a plan view of the corona discharger, and FIG. 3 is a drawing of a shield frame body of the corona discharger from a shield case. FIG. 4 is a partial perspective view, FIG. 4 is an overall configuration diagram of a copying machine as an example in which the corona discharger is used, and FIG. 5 is a diagram showing a mounted state of the corona discharger according to another embodiment of the present invention. FIG. 6 is a perspective view of the dust receiver. 25 ... Shield case, 26 ... Shield frame, 27, 28 ... Insulation block, 29 ... Charge wire, 34 ... Cleaning member.

Claims (1)

[Scope of utility model registration request] 1. A shield case having an opening for discharge, a shield frame body slidably fitted in the shield case, and a pair of insulations fixed to both ends of the shield frame body. A block, a corona discharge wire stretched between the pair of insulating blocks, and an outer side wall of one insulating block of the pair of insulating blocks, and the shield frame body is provided with the shield case. When the insulating block slides inside the shield case together with the shield frame body, the inner surface is slidably contacted with the inner surface of the shield case when the insulating block slides in the shield case together with the shield frame body. A corona discharger including a cleaning member that can be cleaned.